equivalent power flux density limits (epfd) by ssc itu-r ... · defined in sat_oper table, fields...
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Equivalent power flux density limits
(EPFD)
By SSC
ITU-R
ITU HQ Geneva, 6 December, 2018
• Equivalent power-flux density (EPFD) takes into account the aggregate of the emissions from all non-GSO satellites in the direction of any GSO earth station, taking into account the GSO antenna directivity
• EPFD considers pointing of a victim receiving antenna with respect to any source of interference
• Complex calculation methodology considers an interference varying in time and space
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S.1503-38
EPFD
EPFD is calculated:
– Downlink (at the input of GSO earth station receiver)
– Uplink (at the input of GSO space station receiver)
– Inter-satellite (at the input of GSO space station receiver)
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What is EPFD?
Why EPFD?
GSO ArcWanted
Interferer
Wanted/interferer geometry is fixed
Criteria T/T, C/I
Interfering signal path loss
Wanted signal path loss
GSO to GSO
Why EPFD?
Non-GSO to GSO
GSO ArcWanted
Non-GSO
GSO ArcWanted
Non-GSO
Constantly changing wanted vs interferer
geometry
Aggregate effect of interference from
several sources
• Article 22 – Hard Limits to protect GSO from Non-GSO• Hard EPFD limits enable non-GSO FSS systems to share
frequencies with and protect GSO systems without requiring individual coordinations with all the systems worldwide
• FSS non-GSO satellite systems shall comply with the EPFD limits contained in Tables 22-1A, 22-1B, 22-1C, 22-1D, 22-1E, 22-2 and 22-3 of RR Article 22
✓Article 22 contains reference parameters of GSO stations to be protected
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EPFD Limits Regulatory Framework
GSO
NGSO
GSO
NGSO
GSO
NGSO
EPFD on downlink EPFD on uplink
EPFD on inter-satellite path
• Article 9 – coordination trigger limits• specific large earth station requires coordination under RR No.
9.7A with respect to any existing non-GSO satellite systems using the coordination triggers in RR Appendix 5; or
• FSS non-GSO satellite systems requires coordination under RR No. 9.7B with respect to any large earth station (under certain conditions) using the coordination triggers in RR Appendix 5.
✓Coordination trigger limits enable protection of very large specific GSO earth stations
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EPFD Limits Regulatory Framework
• Validation Software is developed in accordance with methodology in Recommendation ITU-R S.1503-2
• Resolution 85 (WRC-03) establishes intermediate arrangements until required software is developed
• “Qualified favourable” finding was given before availability of the software based on the commitment by notifying administration to fulfill Article 22 limits
• Findings under review
• Two parallel developments:• Transfinite Systems Ltd, developed in C++
• Agenium, developed in C#
• Reasons for two developments - Confidence in results: useful for BR and ADMs to be able to check the result of more than one tool
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EPFD Limits Validation Tools
• Circular Letter CR/414, 6 December 2016 contains details of examinations to be carried out in accordance with Resolution 85 (WRC-03).
• The Bureau contacted (end of March 2017) individually each administration having submitted non-GSO systems in the FSS, and requested administrations to submit within three months:
• “traditional” non-GSO parameters in Appendix 4 – orbit parameters, frequency assignments etc.
• The PFD/EIRP* masks accounting for all the features of specific non-GSO systems arrangements
* See also Rec. ITU-R S. 1503-2
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Implementation of Resolution 85 (WRC-03)
App.4 “for space
stations operating in a
frequency band
subject to Nos. 22.5C,
22.5D or 22.5F…”
Undertaken by filing administration
Rec. ITU-R S.1503-2
EPFD calculations
Parameters of non-GSO system delivered by
a notifying administrationInitial data available at the BR
Non-GSO System parameters input
to EPFD calculations
Calculation of pfd / e.i.r.p. masks
pfd / e.i.r.p. masks
Determination of runs to execute
Determination of worst case
geometry
Calculation of EPFD statistics and
limit compliance checking
Decision: pass / fail
BR Input Data to EPFD Calculations
Objectives:
➢ Protection for GSO systems
➢ Flexibility for non-GSO systems
Approach:
➢ Measurable non-GSO system characteristics
➢ Computation of EPFD CDF based on these parameters
Article 22 limits:[EPFD, % time]
by:• Frequency band• Dish size• Service FSS/BSS• Ref. bandwidth
Single non-GSO system verification limits “for all pointing directions” for all GSO systems
• Get familiar with ITU-R Recommendations S. 1503-2/3• PART A – Assumptions
• PART B – Input parameters
• PART C – Generation of pfd/e.i.r.p. masks
• PART D – General description of software algorithms
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Steps required to prepare the data for Article 22 Examination
• Defines non-GSO station transmission “footprint”• For transmitting non-GSO earth station in form of eirp and off-axis eirp mask
• For transmitting non-GSO satellite in form of pfd-mask given either in azimuth-elevation plane or relative to GSO exclusion zone
• For transmitting non-GSO satellite in bi-directional frequency bands in form of eirp and off-axis eirp mask
• Masks are presented in XML-format and embedded in MS Access .MDB container
• https://www.itu.int/ITU-R/go/space-mask-XMLfile/en
• Not included in BR IFIC SRS database
• Are published once examination of non-GSO satellite system is completed
13S.1503-08
Azimuth
Cell i
Elevation
M(Az, E1)
S.1503-07
GSO satellite
GSO arc
iso- linea
longnon-GSO
Dlong
O
z
x
y
Steps required to prepare the data for Article 22 Examination - Masks
• PFD Mask is a powerful instrument, its definition is based on consideration:• Mitigation techniques used towards GSO receiving
stations
• Variation of transmission per sub-satellite latitude
• Provided for each frequency band subject to EPFD
• Can have several different PFD-masks assigned to specific orbital planes or even satellites
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Steps required to prepare the data for Article 22 Examination - Masks
• PFD Mask can take a form of:
PFD as a function of – azimuth and elevation angles from a non-GSO space station towards a point on the Earth
or
PFD as a function of – the separation angle α between a non-GSO space station and the GSO arc, as seen from any point on the surface of the Earth
– the difference Δ L in longitude between the non-GSO sub-satellite point and the point on the GSO arc where the α angle is minimized
• (α, ΔL) PFD Mask is used together with exclusion zone angle α supplied separately from the mask
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Steps required to prepare the data for Article 22 Examination - Masks
Some other important parameters used:
• For Uplink,• The average distance on the Earth’s surface
between co-frequency beams (d) from the non-GSO system (km) and density of co-frequency non-GSO ES (Density)
• Used to derive the number of earth stations operating within GSO footprint defined at -15 dB level. Number of ES within co-frequency beam:
NUM_ES = d * d * Density
• EIRP of representative ES:REP_e.i.r.p. = ES_e.i.r.p. + 10log10 (NUM_ES)
Defined in non_geo table, fields avg_dist and density 16
Steps required to prepare the data for Article 22 Examination – SNS Data
• Representative ES are then populated within GSO beam footprint with separation in longitude and latitude:
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Steps required to prepare the data for Article 22 Examination
S.1503-39
• For uplink and downlink• Minimum elevation angle the non-GSO earth station when it is receiving
or transmitting
Defined in grp table, field elev_min
• For Uplink,• Maximum number of co-frequency tracked non-geostationary satellites
receiving simultaneously
Defined in non_geo table, field nbr_sat_td
• For Downlink,• Maximum number of non-geostationary satellites transmitting with
overlapping frequencies to a given location within the latitude range
Defined in sat_oper table, fields lat_fr, lat_to, nbr_opr_sat
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Steps required to prepare the data for Article 22 Examination
• Masks in XML format are stored in MDB file
• All other parameters are contained in SRS Database.
• To facilitate calculation it is advisable to extract a notice to a separate database only including 1 frequency assignment per each frequency band subject to Article 22, 9.7A, 9.7B examination.
• All data is compiled using EPFDPrepare Tool
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Compiling Data Set
EPFDPrepare Tool
Mask
Operations
Prepare SRS
Data
Masks in
XML
SRS_ALL Database
or SpaceCap
database
Input
Data
Validation
User Input
EPFD
Validation
Software
Mask.MDB
SRS.MDB
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Different scenarios – different databases
Orbital configuration 3Orbital configuration 2Orbital configuration 1
Link type 1 (Service link)
Link type 2 (User link) Other – variation in- GSO Avoidance angle,- Operational latitudes,- Number of satellites
tracked simultaneously
SNS MDB 1 SNS MDB 2 SNS MDB 3
SNS MDB 4 SNS MDB 5 SNS MDB X
MASKS MDB
MASK 1
MASK 2
MASK 3
MASK 4
MASK 5
MASK 6
MASK X
Parameters defined at Notice level (require separate database in case of variation):
1. Earth stations distribution
2. Operational latitudes
3. Number of satellites tracked
4. GSO avoidance angle and method
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Improvements in Rec. S. 1503-3SNS MDB
MASKS MDB
MASK 1
MASK 2
MASK 3MASK
4
MASK 5
MASK 6
All Freqs All BeamsAll Earth Stations
MASK 1
MASK 2
MASK 3MASK
4
MASK 5
MASK 6
Non-GSO operating parameters Masks
PFD/EIRP Masks
Single SNS MDB for all differentnon-GSO operating scenarios
• LEO with orbit altitude of 1000 km
• 5 Orbital Planes with 5 satellites in each orbit
• Using steerable beams
• Minimum Elevation angle is 20 degrees
• PFD Mask in AzEl format
• Only 19.7-20.2 GHz band will be analyzed
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Test case
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Test case
This slide contains animations
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Exclusion zone is defined in the mask
This slide contains animations
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Red zone (low transmission level) is 20 degrees
• Make sure that mask covers all ranges of latitudes, azimuth/elevation, alpha/deltaLongitude
• Exception, If same values are applicable to all latitudes of SSP provide only latitude=0 tables
• If appropriate mask is given but EPFD is still exceeded, consider increasing sampling of latitude, azimuth/elevation
• Note the worst-case geometry latitude identified by the software, include latitude table as close as possible to identified worst-case latitude
• For latitude, azimuth/elevation identified in EPFD software in a calculation step which can not be found in the mask, the software would use closest tables in the mask
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Defining mask
ITU-R Recommendation S.1503-2 Functional description to be used in developing software tools for
determining conformity of non-geostationary-satellite orbit fixed- satellite system networks with limits contained in Article 22 of the Radio Regulations
EPFD software web-pagehttp://www.itu.int/ITU-R/go/space-epfd/en
EPFD Support Forumhttp://groups.itu.int/epfd/en-us/epfdforum.aspx
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Resources
• Given the masks in XML-format and source SRS database to prepare input databases for EPFD validation
• Exercise 1: Using PFD-mask with no mitigation techniques applied
• Exercise 1: Using PFD-mask with restricted PFD-level in areas where there is a potential to affected victim GSO receiver
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Exercise Overview
EPFD Validation
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Locate EPFD exercise files on handout USB stick:[USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\
Install GIBC with EPFD Modules
From BR IFIC (Space Services) DVD-ROM or USB stick:[USB drive]:\BRIFIC-2884_S\BR_Soft\GIBC\Setup.exeor
http://www.itu.int/en/ITU-R/software/Pages/epfd.aspx
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Exercise setup
Task:
Given an input data:Database with non-GSO CR/C filing NSKY SRS_SOURCE.MDB[USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\SRS_SOURCE.MDB
XML Mask Data:Downlink PFD Mask [USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\Exercise_1_PFD_Mask_104_id_1.xml
Your task is:- to prepare two input databases (SRS Data and Mask Data) required for EPFD
Validation- perform EPFD validation and review the results of EPFD validation.
Results are reproduced on the USB-stick:[USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\ReadyFiles\
Step-by-step guide for offline exercise is given in the annex.
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Exercise No. 1 Preparing data for EPFD Validation
Task:
Given:Database NSKY_SRS.MDB prepared in first exerciseAdjusted XML Mask :
Downlink PFD Mask [USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\Exercise_2_PFD_Mask_104_id_1.xml
Your task is:- to prepare new Mask Data database required for EPFD Validation.- perform EPFD validation and review the results of EPFD validation.Results are reproduced on the USB-stick:[USB drive]:\Space Workshop\Day 4\Non-GSO EPFD\ReadyFiles\
Step-by-step guide for offline exercise is given in the annex.32
Exercise No. 2 Preparing data for EPFD Validation
Start with GIBC
• Start GIBC
• Navigate to EPFD tab
• Start EPFDPrepare
Prepare EPFD Input Data
• Select Create Masks Database
Prepare EPFD Input Data
• Click New Mask MDB File
Prepare EPFD Input Data
• Click Store Mask(s) to MDB
• In a dialog Select file ‘Excercise_1_PFD_Mask_104_id_1.xml’
• Click ‘Ok’
• Mask validation window would appear
• Click ‘Save mask in MDB’
Prepare EPFD Input Data
• Click ‘Save Changes’
• Save mask under the name NSKY_Mask_Exercise1.mdb
• Close the window to return to EPFD Prepare
Prepare EPFD Input Data
• Select Prepare SRS Data
Prepare EPFD Input Data
• Select Prepare SRS Data
This slide contains animations
Start EPFD
• Enter notice ID - 104
• You can choose additionaloptions:• Full WCG Down Check• Use Dual Timestep
• Check ‘Use Dual Timestep’ to speed-up calculations
• You can start calculations using Transfinite EPFD tool or Agenium EPFD Tool by clicking corresponding buttons.
• When finished click ‘View Results’
View Results
This slide contains animations
EPFD Limits are exceeded.
Need to use adjusted PFD Mask which is employing exclusion zones
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Exercise No. 1 Outcome
Repeat steps used to create NSKY_Mask_Exercise1.MDB but use other XML mask USB:\Space Workshop\Day 4\Non-GSO EPFD\Excercise_2_PFD_Mask_104_id_1.xml
Save MDB Mask file under NSKY_Mask_Exercise2.MDB
No need to create NSKY_SRS.MDB file, we will reuse NSKY_SRS_Exercise1.mdb
Run EPFD Validation using:
NSKY_Mask_Exercise2.MDB
NSKY_SRS_Exercise1.MDB43
Exercise No. 2
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Exercise No. 2Results
This slide contains animations
